Voidable cover interlock

ABSTRACT

A switch enclosure having an openable cover and a handle operable externally of the enclosure for operating a switch therein, is provided with a voidable interlock that normally prevents opening of the cover when the handle is in the switch ON position. The interlock consists of a single screw mounted to the handle and movable therewith. Under normal operating conditions, with the handle in the ON position the screw blocks opening of the cover and in the handle OFF position the screw is aligned with a notch in the cover that provides clearance thereby permitting the cover to be opened. When the handle is in the switch ON position a formation thereof covers the notch so that objects may not be inserted through the notch into the enclosure. Also, when the handle is in ON position, the interlock limits movement of the cover from its fully open position to a partly rather than completely closed position and in this partly closed position it is not possible to apply a padlock to maintain the cover in this position. The head of the screw is accessible externally of the enclosure to permit operation of the screw to a retracted position wherein the interlock is voided and the cover may be opened whether the handle is in switch ON or OFF position.

United States Patent 91 Clement [451 May 22,1973

[ .4] VOIDABLE COVER INTERLOCK [75] Inventor: Ralph C. Clement,Bellefontaine,

Ohio

[73] Assignee: l-T-E Imperial Corporation,

Philadelphia, Pa.

221 Filed: Jan.24, 1972 211 App1.No.: 220,095

3,339,047 8/1967 Rys et al. ..200/50 A Primary Examiner-J. R. Scott IAztorney-Ostrolenk, Faber, Gerb & Soffen ABSTRACT A switch enclosurehaving an openable cover and a handle operable externally of theenclosure for operating a switch therein, is provided with a voidableinterlock that normally prevents opening of the cover when the handle isin the switch ON position. The interlock consists of a single screwmounted to the handle and movable therewith. Under normal operatingconditions, with the handle in the ON position the screw blocks openingof the cover and in the handle OFF position the screw is aligned with anotch in the cover that provides clearance thereby permitting the coverto be opened. When the handle is in the switch ON position a formationthereof covers the notch so that objects may not be inserted through thenotch into the enclosure. Also, when the handle is in ON position, theinterlock limits movement of the cover from its fully open position to apartly rather than completely closed position and in this partly closedposition it is not possible to apply a padlock to maintain the cover inthis position. The head of the screw is accessible externally of theenclosure to permit operation of the screw to a retracted positionwherein the interlock is voided and the cover may be opened whether theban die is in switch ON or OFF position.

9 Claims, 8 Drawing Figures PATENTEDHAYZZIQYS sum 1 [IF 2 C PUSH ONPATENTED W22|973 3. 735,064

SHEET 2 [IF 2 VOIDABLE COVER INTERLOCK This invention relates generallyto switch enclosures and more particularly relates to an enclosure ofthis type having novel voidable interlock means that normally preventsthe enclosure cover from being opened when the switch is ON.

Many electrical switches, including molded case circuit breakers, areoften mounted within a metal enclosure having a separate operatinghandle mounted on the outside of the enclosure and connected to thehandle of the switch inside the enclosure for operating this switch. Asa safety feature, under normal conditions an interlock means preventsopening of the enclosure cover when the enclosure mounted handle is inthe switch ON position. However, for servicing of the switch it is oftennecessary to open the enclosure when the handle thereof is in the switchON position. Thus, the cover interlock must be voidable. Further, theinterlock must be so constructed that with the enclosure handle in theswitch ON position the enclosure cover cannot be locked in a partiallyclosed position.

Accordingly, the primary object of the instant invention is to provide anovel inexpensive cover interlock for a switch enclosure.

Another object is to provide an interlock of this type that isdefeatable.

Still another object of this invention is to provide an interlock ofthis type including a single screw element threadably mounted directlyto the enclosure handle and accessible externally of the enclosure formovement between an operating and a voided position.

A further object is to provide interlock means of this type which, whenthe enclosure mounted handle is in the switch ON position, limitsclosing movement of the cover to a position wherein it is not lockable.

These objects as well as other objects of this invention will becomereadily apparent after reading the following description of theaccompanying drawings in which: I

FIG. 1 is a front elevation of a switch enclosure constructed inaccordance with teachings of the instant invention, with the enclosurecover closed and the enclosure handle in the switch OFF position.

FIG. 2 is a side elevation looking in the direction of arrows 2-2 ofFIG. 1.

FIG. 3 is a front elevation of the switch enclosure of FIG. 1 with theenclosure cover pivoted to open position.

FIG. 4 is a view similar to that of FIG. 1 with the enclosure handle inthe switch ON position.

FIG. 5 is a side elevation looking in the direction of arrows 5-5 ofFIG. 4.

FIG. 6 is a bottom view looking in the direction of arrows 6-6 of FIG.4.

FIG. 7 is a view similar to that of FIG. 6 with the enclosure cover onlypartly closed.

FIG. 8 is a perspective of the enclosure mounted switch handle.

Now referring to the Figures, rectangular switch enclosure 11 isprovided with openable cover 12 connected thereto at the forward freeedge of side wall 11a by side hinges 13, 14. Screws 15, 16 secureinsulating block 17 to the rear wall 18 of the closure 11. Insulatingblock 17 supports three identical switch heads 19a, 19b and 190, each ofa type fully described in US Pat. No. 3,259,723 issued July 5, 1966 toRS. Davis for an Electric Switch Head. Each switch head 19a, 19b, 19c

is connected in electrical series with an individual cartridge fuse 21,also mounted to insulating block 17.

All three switches 19a, 19b, 19c are connected to the offset portion 22of operating bail 23 whose ends are connected at pivots 24, 25 to sidewalls 11a, 11b, respectively, of enclosure 11. Over center torsionspring 26 is anchored at one end thereof to enclosure side wall 11a bypin 27 and the other end 28 of torsion spring 26 is wound about offsetportion 22 of bail 23. The end of bail 23 mounted to pivot 25 isprovided with elongated flattened formation 29 having apertures (notshown) on opposite sides of pivot 25 to receive formations 31, 32 whichproject inward from support section 33 of enclosure operating handle 30to provide a good driving connection between handle 30 and bail 23.

Support section 33 of handle 30 is disposed adjacent the inner surfaceof enclosure side wall 1 lb with curved operating portion 34 of handle30, which is at right angles to handle portion 33, being disposedslightly forward of the forward edge of side wall 11b and extendingthereover. Handle support section 33 also includes clearance aperture 36for bail pivot 25 and rear notch 37 which cooperates with ear 68 struckfrom side wall 1 lb, to limit pivotal movement of enclosure handle 30.

The rear end 41 of cover catch 40 is welded to side wall 11b near theupper end thereof and includes deflectable locking portion 42 whichextends forward of the forward edge of enclosure side wall 11b and isprovided with aperture 43 to receive the shackle of a padlock (notshown). With cover 12 fully closed, locking section 42 protrudes throughcover slot 44 so that a padlock (not shown) connected at aperture 43will lock cover 12 closed. Handle 30 is provided with elongated slots38, 39 that are accessible when handle 30 is in its respective ON andOFF switch positions to receive padlocks for locking handle 30 in theserespective positions.

Interlock screw 50 is threadably mounted to handle supports portion 33at a position slightly forward of locking slot 39. Screw head 51 isaccessible externally of enclosure 11 to back screw 50 from itsoperating position shown in the drawings to a voided position whereinthe free end 52 of screw 50 is flush with handle support section surface53, for a reason to be hereinafter explained. The free end ofinterlockscrew 50 is slightly enlarged or the end threads are staked sothat screw 50 may not be dismounted from han'dle30.

Cover 12 is provided with notch 55 along the edge thereof remote fromhinges 13, 14 to provide clearance for handle 30 and is provided with aninterlock cut-out or notch 56 that is aligned with and providesclearance for the body of interlock screw 50 when enclosure handle 30 isin its switch OFF position of FIG. 1. When handle 30 is in its switch ONposition, formation 54 extending inward from handle support section 33is disposed immediately behind interlock notch 56 to effectively closethe latter against insertion of foreign objects into enclosure 11.

As seen in FIG. 4, when handle 30 is in its switch ON position the bodyof interlock screw 50 is out of alignment with interlock notch 56 incover 12 thereby blocking movement of cover 12 to its open position.However, for purposes of servicing the electrical device withinenclosure 1 1, cover 12 may be opened after handle 30 is operated to theswitch ON position by merely backing interlock screw 50 to the rightwith respect to I FIG. 6 so that the body of screw 50 will not blockmovement of cover 12.

For those situations in which handle 30 is operated to the switch ONposition after cover 12 is open, interlock screw 50 in its operatingposition (shown) will prevent cover 12 from moving to a fully closedposition so long as handle 30 remains in switch ON position. Under thesecircumstances interlock screw 50 will limit movement of cover 12 to apartially closed position and in this partially closed position covercatch aperture 43 is, for the most part, disposed behind the front wallof cover 12 so that aperture 43 is inaccessible to receive the shackleof a padlock.

Thus, it is seen that the instant invention provides a very inexpensiveconstruction for a voidable cover interlock for a switch enclosure. Inparticular, such voidable interlock consists of a retractable screwmounted to the enclosure handle and positioned to cooperate with a covernotch which permits opening of the cover when the handle is in switchOFF position. However when the handle is in switch ON position theinterlock screw is so positioned that it blocks opening of the cover.

Although the invention has been described above with respect to itspreferred embodiments, it will be understood that many variations andmodifications will be obvious to those skilled in the art. It ispreferred, therefore, that the scope of the invention be limited not bythe specific disclosure herein but only by the appended claims.

The embodiments of the invention in which an exclusive privilege orproperty is claimed are defined as follows:

1. in combination, an enclosure for a switching device,; an openablecover for said enclosure; an operating handle mounted to said enclosureand movable between a first and a second position to operate a switching device within said enclosure to its respective closed and openpositions; voidable interlock means operated to third and fourthpositions by operation of said handle to said first and secondpositions, respectively; said interlock means when in said thirdposition blocking opening of said cover and when in said fourth positionpermitting opening of said cover; when said handle is in said firstposition and said cover is closed, said interlock means being accessiblefrom outside of said enclosure for movement of said interlock means froman operating position to a voided position; said interlock means beingcomprised of a cover blocking element mounted to said handle; with saidcover closed, said handle in said first position and said interlockmeans in 4 said operating position, said element being positioned infront of said cover.

2. A combination as set forth in claim 1 also including additional meansoperative when said cover is fully closed to receive a lock for holdingsaid cover in closed position; with said cover open, said handle in saidfirst position, and said interlock means in said operating position,said interlock means preventing closing of said cover beyond a partiallyclosed position wherein said additional means is inaccessible forreception of a padlock.

3. A combination as set forth in claim 2 in which the additional meansincludes a cover catch element secured to said enclosure and extendingforward thereof, said cover having an aperture to receive said covercatch element, said cover catch element having a lock receiving aperturepositioned in front of said cover when the latter is closed and behindsaid cover when the latter is in said partially closed position.

4. A combination as set forth in claim 1 in which said element iswithdrawn from in front of the cover, when said interlock means is insaid voided position, by being repositioned relative to said handle.

5. A combination as set forth in claim 4 in which the cover includes aclearance notch aligned with said element to permit opening of saidcover when said handle is in said second position.

6. A combination as set forth in claim 5 in which said handle includesan offset formation within said enclosure constructed and positioned inalignment with said clearance notch to block entry of objects into saidenclosure through clearance notch when said handle is in said firstposition.

7. Apparatus as set forth in claim 6 in which the element is a screwthreadably mounted to said handle.

8. Apparatus as set forth in claim 5 in which the enclosure includes arear wall confronting said cover when the latter is in closed position,and side walls extending forward from said rear wall; said handle beingmounted on a pivot at one of said side walls.

9. Apparatus as set forth in claim 8 in which said handle includes firstand second sections extending in oppo-site directions from said pivot,with said handle in said first position, said first section extendingforward of said enclosure and being depressible for operation of saidhandle to said second position; with said handle in said secondposition, said second section extending forward of said enclosure andbeing depressible for operation of said handle to said first position.

1. In combination, an enclosure for a switching device,; an openablecover for said enclosure; an operating handle mounted to said enclosureand movable between a first and a second position to operate a switchingdevice within said enclosure to its respective closed and openpositions; voidable interlock means operated to third and fourthpositions by operation of said handle to said first and secondpositions, respectively; said interlock means when in said thirdposition blocking opening of said cover and when in said fourth positionpermitting opening of said cover; when said handle is in said firstposition and said cover is closed, said interlock means being accessiblefrom outside of said enclosure for movement of said interlock means froman operating position to a voided position; said interlock means beingcomprised of a cover blocking element mounted to said handle; with saidcover closed, said handle in said first position and said interlockmeans in said operating position, said element being positioned in frontof said cover.
 2. A combination as set forth in claim 1 also includingadditional means operative when said cover is fully closed to receive alock for holding said cover in closed position; with said cover open,said handle in said first position, and said interlock means in saidoperating position, said interlock means preventing closing of saidcover beyond a partially closed position wherein said additional meansis inaccessible for reception of a padlock.
 3. A combination as setforth in claim 2 in which the additional means includes a cover catchelement secured to said enclosure and extending forward thereof, saidcover having an aperture to receive said cover catch element, said covercatch element having a lock receiving aperture positioNed in front ofsaid cover when the latter is closed and behind said cover when thelatter is in said partially closed position.
 4. A combination as setforth in claim 1 in which said element is withdrawn from in front of thecover, when said interlock means is in said voided position, by beingrepositioned relative to said handle.
 5. A combination as set forth inclaim 4 in which the cover includes a clearance notch aligned with saidelement to permit opening of said cover when said handle is in saidsecond position.
 6. A combination as set forth in claim 5 in which saidhandle includes an offset formation within said enclosure constructedand positioned in alignment with said clearance notch to block entry ofobjects into said enclosure through clearance notch when said handle isin said first position.
 7. Apparatus as set forth in claim 6 in whichthe element is a screw threadably mounted to said handle.
 8. Apparatusas set forth in claim 5 in which the enclosure includes a rear wallconfronting said cover when the latter is in closed position, and sidewalls extending forward from said rear wall; said handle being mountedon a pivot at one of said side walls.
 9. Apparatus as set forth in claim8 in which said handle includes first and second sections extending inoppo-site directions from said pivot, with said handle in said firstposition, said first section extending forward of said enclosure andbeing depressible for operation of said handle to said second position;with said handle in said second position, said second section extendingforward of said enclosure and being depressible for operation of saidhandle to said first position.